<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>出错啦</title>
    <style>
        .hit-the-floor {
            color: #fff;
            font-size: 12em;
            font-weight: bold;
            text-shadow: 0 1px 0 #ccc,
            0 2px 0 #c9c9c9,
            0 3px 0 #bbb,
            0 4px 0 #b9b9b9,
            0 5px 0 #aaa,
            0 6px 1px rgba(0, 0, 0, .1),
            0 0 5px rgba(0, 0, 0, .1),
            0 1px 3px rgba(0, 0, 0, .3),
            0 3px 5px rgba(0, 0, 0, .2),
            0 5px 10px rgba(0, 0, 0, .25),
            0 10px 10px rgba(0, 0, 0, .2),
            0 20px 20px rgba(0, 0, 0, .15);
        }

        .hit-the-floor {
            text-align: center;
        }


    </style>
</head>
<body>
<div class="hit-the-floor">404</div>
</body>
</html>